Extensible ladder constructions



March 21, 1961 H. SUROFF ETAL EXTENSIBLE LADDER CONSTRUCTIONS 5 Sheets-Sheet 2 Filed Nov. 17, 1955 INVENTORS HYM/W SUFPOFF' BYLEONARD SUROFF MLQMM A TORNEY H. SUROFF ETAL EXTENSIBLE LADDER CONSTRUCTIONS March 21, 1961 5 Sheets-Sheet 3 Filed Nov. 17, 1955 D llns INVENTORS A YMAN SUEOF'F Asa/mm: Super;

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ATTQRNEY EXTENSIBLE LADDER CONSTRUCTIONS Hyman Surofi and Leonard Snrolf, both of 329 E. 54th St., Brooklyn, N .Y.

Filed Nov. 17, 1955, Ser. No. 547,413

18 Claims. (Cl. 182-466) This invention relates generally to extensible ladder constructions.

An object of the invention is to provide a ladder construction-having stiles independently adjustable to provide either uniform or non-uniform extensions, in order that the ladder be supported firmly either on a common level, or at different levels, as, for instance, where the stiles are supported upon steps at different levels, and wherein one or more additional steps may be provided for the ladder in either the uniformly or non-uniformly extended position.

Another object of the invention is to provide a ladder construction wherein the additional steps may be folded into interfitting relation with parts of the stiles so that the stiles which may be extended and the additional steps may be telescoped into interfitting relation for housing or transporting the ladder.

Another object of the invention is to provide a ladder construction of the type indicated which is of lightweight construction consistent with strength and structural rigidity, contractible into convenient and compact form, simple in design and construction, convenient for use, and reliable in operation.

Other objects of the invention will be set forth hereinafter, or will be apparent from the description and the drawings, in which are illustrated embodiments exemplifying the invention.

The invention, however, is not intended to be restricted to any particular construction, or any particular arrangement of parts, or any particular application of any such construction or arrangement of parts, or any specific method of operation or use, or any of the various details thereof, even where specifically shown and described herein, as the same may be modified in various particulars, or may be applied in many varied relations, without departing from the spirit and scope of the claimed invention, of which the exemplifying embodiments, herein shown and described, are intended only to be illustrative, and only for the purpose of complying with the requirements of the statutes for disclosure of an operative embodiment, but not to show all the various forms and modifications in which the invention might be embodied.

On the drawings, in which the same reference characters refer to the same parts throughout, and in which are disclosed such practical constructions,

Fig. 1 is a perspective view, illustrating a ladder embodying features of the invention disposed with its stiles extended and supported at diiferent levels on a flight of steps;

Fig. 2 is a perspective view, illustrating a ladder embodying features of the invention and with the stiles folded closed, but portions of the stiles being extended so that the ladder may be supported at different levels on a flght of steps in a different manner;

Fig. 3 is a vertical cross-sectional view, to enlarged scale, and substantially on line 3-3 of Fig. 5, of a portion of the front stile member and its companion extension member of a ladder of the type noted, certain parts Patented Mar. 21, 1961 ire 2 for producing additional steps for the ladder being shown in collapsed and telescoped position.

Fig. 4 is a vertical cross-sectional view of substant1ally the same portion as Fig. 3, and to substantially the same scale, but taken substantially on line 44 of Fig. 5;

Fig. 5 is a horizontal cross-sectional view of substantially the same portions as Figs. 3 and 4, and to substantially the same scale, but taken substantially on line 55 of Fig. 4;

Fig. 6 is a fragmentary vertical sectional View of a portion of the rear stile member and its companion ex tension member when extended with relation to each other, the section being taken substantially on the line 6-6 of Fig. 7;

Fig. 7 is a sectional view of the stile member as taken substantially on the line 7--7 of Fig. 6;

Fig. 8 is a detail sectional view, to enlarged scale, of the members-latching means as seen from line 88 of Fig. 5;

Fig. 9 is a fragmentary front elevational view of a front section of a ladder having parts such as shown in Figs. 3, 4 and 5, the construction being broken away, one pair of step parts being shown completely extended and interlocked, and other step parts being shown in other intermediate positions;

Fig. 10 is a detail vertical cross-sectional view, on the line 1010 of Fig. 9, certain of the parts being broken away;

Fig. 11 is a view similar to Fig. 9, the width being re duced by breaking away the collapsible steps, the stiles being broken away, to illustrate a modified form of an extensible and collapsible ladder;

Fig. 12 is a view similar to Fig. II, but to reduced scale, illustrating a further modified form of an extensible ladder construction;

Fig. 13 is a detail cross-sectional view, on the line 1313 of Fig. 12;

Fig. 14 is a detail cross-sectional view, on the line 1414 of Fig. 13; and

Fig. 15 is a fragmentary vertical cross-sectional view, showing the ladder construction of Fig. 12 substantially in fully retracted position.

Referring to the drawings, and more particularly to Figs. 1 to 10 thereof, there is shown an adjustable step ladder 10 having front and rear sections 12 and 14, respectively, which, as in the usual step ladder construction, may be pivotally connected in any suitable manner at their upper ends to a platform 16. The front and rear sections may be interconnected by foldable straps 18 of conventional constructtion to limit movement of the sections as they move from the folded condition of Fig. 2 to the opened up condition of Fig. 1.

Front section 12 may comprise a pair of structurally similar, laterally spaced stile members 20, 20' formed of longitudinally extending channel members. A series of vertically spaced steps 22 extend transversely between and are secured to stile members 20, 20' in any suitable manner. Cooper-atively associated with stile members 20, 20' is an extension section 24 which comprises a pair of structurally similar extension members 26 and 26 whichv may be formed of longitudinally extending channel memparts 28 and 30 may be structurally similar, andconstituted by channel members, each of said step parts having its inner end 32 pivotally mounted to the inner face 34 of member 26 by means of a hinge 36. Hinge 36 may comprise a pair of hinge plates 38, 38, pivotally connected to each other by a hinge pin 40, plates 38 and 38' being secured to member 26 and a companion step part, respectively, in any suitable manner, for example, by means of suitable fastener elements 42.

Each step part 28, 30, is pivotally movable in an up- Ward direction from an extended position (Figs. 1 and 9) in which said step part extends transversely between the extension members 26 and 26, and, at thelimit, is substantially perpendicularly disposed to its respective extension member, to a retracted position (Figs. 3-5), in which said step part extend-s longitudinally of and interiits within extension member 26. Extension member 26 is fully retractible inwardly of its companion stile member when the step parts are retracted so as to interfit with the extension member, and thus the stile member, in the fully retracted position of the extension member, constitutes a housing for the extension member and the step parts carried thereby. Step parts 28 and 39 may be dimensioned to be substantially one-half of the transverse distance between extension members 26 and 26, so that the step parts, when in the extended position of Fig. 9, have their free ends 44 disposed substantially medially between members 26 and 26.

Step parts 28 and 30 of extension members 26 and 26' are adapted to be disposed in longitudinal alignment in certain adjusted positions of the members. In order releasably to interconnect the adjacent free ends 44 of the step parts in their longitudinally aligned positions, there is provided a bridging member 46 which may comprise a channel member which interfits with the step parts. Member 46 is slidably movable relatively to the step parts from an extended position (see aligned parts in Fig. 9) where member 46 bridges the adjacent free ends 44 of said step parts to interconnect them, to a position 46' (see Figs. 3, 5 and 9) where member 46 is retracted inwardly of either one of the aligned pair of step parts and out of bridging relation with the other step part. In

such retracted position, member 46 is limited by hinge plate 38'. Each aligned pair of step parts, thus interconnected, collectively defines a rigid step 48 which extends transversely between extension members 26 and 26.

When extension members 26 and 26 are uniformly extended, step parts 28 and 30 of member 26 are adapted to align with their companion step parts 2 8 and 30, respectively, of member 26' ('Fig. 1). Where extension members 26 and 26' are not extended sufficiently to permit the pivotal movement of the step parts 28 to their extended positions, the lower pair of step parts 30 may be extended and interconnected to form a single extension step 48. Thus, when the extension members are uniformly extended, one or more extension steps 48 may be defined by the companion step parts, and any number of companion pairs of step parts may be provided, the two extension step embodiment illustrated being merely by way of example.

In the non-uniformly extended condition of extension members 26 and 26, or where only one of such members is extended, an adjustment may be obtained in which one of the step parts 28 and 30 of member 26 is aligned and connected to a companion one of the step parts 30 and 28, respectively, of member 26 in order to define an extension step 48 formed by an aligned and connected pair of step parts 28 and 30. Where a greater number of step parts are provided on the extension members, a greater number of extension steps 48 may be defined between such members in the non-uniform association. When the bridging members are in their retracted positions 46', they are confined within and interfit with a companion step part in order not to interfere with the described retraction of the step parts and the extension members.

In order releasably to latch the extension members in a plurality of spaced longitudinally adjusted positions relative to their companion stile members, each stile member is provided with one or more vertically spaced latching devices 50, here shown as a pair for each stile member. Each latching device 50 may include an axially reciprocable pin 52 (Fig. 8) which is adapted to be brought into registry with and then to engage in one of a series of spaced apertures 54 which are formed in wall 56 of the extension members. The apertures may be spaced so that a pair of pins 52 of devices 50, carried by each stile member 20 and 20' and vertically spaced from each other along the stile member, may simultaneously register with a correspondingly spaced pair of apertures 54. Pin 52 may be disposed in a housing 57 secured to wall 58 of a companion stile member 20, 20 by fastener elements 60, wall 58 being apertured, at 62, for the extension of pin 52 therethrough. Wall 64 of housing 57 may have an aperture 66 therethrough for projection of guide pin 68 of the latch member. Surrounding pin 63 and extending between peripheral shoulder 70 and wall 64 is a compression spring 72 which tends to move the latch member into aperture 54. In order selectively to release pin 52 from engagement in a registered aperture 54, and thus to permit longitudinal adjustment of a companion extension member, the latch member may have a manually operable lever 74 extending through a longitudinal slot 76 (Fig. 7) provided in housing 57, said slot having a laterally extending portion 78 which is adapted to receive lever 74 by turning pin 52 to latch the member out of engagement with its companion extension member. In practice, lever 74 is manipulated manually to the outer end of slot 76, to retract pin 52 from engagement in a registered aperture 54, and is thereafter rocked to interengage in portion 78 to latch said member in retracted position. Thus, each extension member is independently extensible and retractible relatively to a companion stile member, and may releasably and positively be latched in a plurality of adjusted positions by means of latching devices 50.

The rear section 14 of the ladder may comprise a pair of structurally similar, laterally spaced stile members 80, 80, which may be formed of longitudinally extending channel members. A series of vertically spaced steps 82 may extend transversely between and be secured to stile members 86 80'; however, if desired, steps 82 may be dispensed with, and any suitable brace structure may be provided between the stile members.

As best shown in Figs. 6 and 7, stile members 80 and 80 have longitudinally adjustable extension members 84 which are in the form of longitudinally extending channel members which interfit with their companion stile members. Extension members 84 are independently adjustable longitudinally in the manner described above in detail with reference to extension members 26, 26'. Extension members 84 may be fully retracted into their companion stile members (Fig. 1). Each of extension members 84 is adapted to be latched releasably in a plurality of spaced longitudinally adjusted positions by a pair of vertically spaced latching devices 50 which have pins 52 which are engageable in registered apertures 54 extending through the extension members. Accordingly, the front and rear sections of the ladder may be similarly constituted except where only front section 12 is provided with the retractible extension step arrangement heretofore described.

With reference to Fig. 11, there is shown a ladder 10' which may in certain respects be similar structurally to ladder 10. Extension device or section 24' of ladder 10 may comprise a pair of structurally similar extension members 90 and 98, which may correspond to members 26 and 26'. Extension members 90 and 90 may be formed of channel members which are carried upon and interfitted with companion stile members 20 and 20', and which are independently adjustable longitudinally in the manner described in detail above. Each of extension members 90, 99 has a step 92 pivotally mounted thereto by means of a hinge 36, said step being of a longitudinal extent substantially corresponding to the distance between the extension members. The steps 92 of the extension members d9, 90 are spaced from each other along the latter; each step is movable pivotally from an extended position, as Where upper step 92 (Fig. 11) extends transversely between the extension members, to a retracted position 92 where the lower step is shown extending longitudinally of its companion extension member and interfitting therewith.

In order releasably to secure the free end 94 of each step 92 in the extended position thereof to an opposite extension member, that free end may be provided with a latching tongue 96 to interengage with a complementarily aligned fitting 98 secured to a wall 100 of the opposed extension member. A series of such fittings may be secured to the extension members in vertically spaced relation so that the steps in their extended positions may be secured to the extension members in uniformly or nonuniformly adjusted relation to their companion stile members. The hinge plates 38 of hinges 36 may be secured to walls 100 of the extension members by means of spacer blocks 102 in order that steps 92 may be retracted without interference from fittings 98. As shown, steps 2 will alternate between members 90 and 90. Extension section 24 may be provided with any desired number of steps 92, which are to be folded upwardly into interfitting relation with their respective extension members so that the extension members may be retracted inwardly of their companion stile members.

Referring to Figs. 12 to 15, there is shown a ladder 104 which difiers from the previously described embodiments in certain respects. Ladder 1%4 may comprise a pair of laterally spaced stile members 106 and 106 which are constituted by channel members. The stile members may have a plurality of steps 108 extending transversely between and secured to the members. The lowermost step is disposed at the lower end of the stile members and is secured to both stile members by means of angle brackets 119. Carried Within and adjustable longitudinally relatively to stile member 1% are extension members 112 and 114 which are constituted by channel members which interfit with said stile member. Extension members 112 and 114 are extensible to the positions shown in Figs.

12 and 13, for example, from the fully retracted positions thereof shown in Fig. 15.

Extension members 112 and 114 each has an end of a step 116 or 118, respectively, fixedly secured to the member. Steps 116 and 118 limit retraction of their companion extension members (Fig. 15). Extension members 112 and 13.4 differ from extension members 112 and 114, respectively, in that steps 116 and 118 are not fixedly secured to members 112 and 114. Thus members 112 and 114 are adjustable independently relative to the stile members and to their companion extension members 112 and 114, respectively. Steps 116 and 118 are of a longi tudinal extent substantially corresponding to the distance between their companion extension members, but at the ends adjacent members 112 and 114' are free of permanent connection. The free end 129 of each step 115 or 118 is adapted to be secured releasably to a companion extension member 112' or 114' at vertically spaced positions by means of laterally spaced latching devices 122. secured to the underside of each step in any suitable manner.

Each latching device 122 may comprise a spring retracted and rotatable latch member 124 which terminates in a lateral latch part 126. Latch part 126 is intended to be passed through a companion longitudinal slot 128 which extends through the extension members. In practice, latch part 126 is aligned with slot 128, and is pulled or pushed through the slot against the bias of spring 130; part 126 is intended to be rotated out of alignment with slot 128 in order to secure the free end of the step to a companion extension member.

Each of extension members 112 and 114 is provided with a vertically spaced series of pairs of aligned slots 128, each pair of slots being spaced to correspond to the desired spacing of the steps. Thus each companion pair of extension members 112, 112' and 114, 114' may be uniformly or non-uniformly extended relatively to the stile members, and the free ends 120 of the steps then releasably secured in position to respective extension member 112 or 114' by means of latching devices 122 carried by the steps. The extension members are releasably latched in their longitudinally adjusted positions relative to their companion stile members by means of pairs of vertically spaced latching devices 56 which interengage with apertures 54 provided in the extension members. The arrangement of devices 50 may correspond to that of ladder 1! but ladder 104 has an additional extension member carried by each of the stile members thereof in which a series of apertures 54 is also provided. Thus each latching device 50 is adapted to interengage with aligned apertures 54- provided in the extension members carried by each of the stile members.

The ladders aforedescribed may be formed of any suitable material, such as magnesium, aluminum, or other materials which may be found preferable, or which may provide sufficiently strong and lightweight construction. Ladders as here described provide extension members which may be extended uniformly or non-uniformly so that the ladder stiles may be supported firmly either on a common level, or upon vertically spaced levels, in order to permit such ladders to be supported on surfaces of irregular character. As shown in Fig. 1, the front and rear sections of the ladder may be supported on steps at different levels, the extension members of the front stiles being uniformly extended. As shown in Fig. 2, the ladder sections may be folded, but in such case a pair of opposed stiles are extended to a degree different from that of the other opposed stiles, so that these sections, non-uniformly extended, may be supported from steps at different levels.

Many other changes could be effected in the particular constructions, and in the methods of use and construction, and in specific details thereof, hereinbefore set forth, without substantially departing from the invention intended to be defined herein, the specific description being merely of embodiments capable of illustrating certain principles of the invention.

What is claimed as new and useful is:

1. A ladder, comprising a pair of stile members, means for maintaining said stile members in laterally spaced relation, an extension device cooperatively associated with said stile members, said extension device comprising a pair of extension members, each extension member and a respective stile member being interfitted one within the other and being slidable and longitudinally adjustable relatively to its stile member, each of the extension members having a face disposed in opposition to the like face of the opposite disposed face of the other extension member, and step means mounted on each of the opposed faces to move with that face of and with relation to the other of said extension members, said step means being capable of extension to and engagement with the opposed face of the other extension member, each of said exten-' 'sion members being independently extensible longitudinally relatively to its respective stile member.

2. A ladder, comprising a pair of stile members, means for maintaining said stile members in laterally spaced relation, an extension device cooperatively associated with said stile members, said extension device comprising a pair of extension members, each of the stile members being interfitted with an extension member and held against separation therefrom while permitting relative longitudinal adjustments, step means mounted on oneof the extension members and extending toward the other of said extension members, said extension members being independently adjustable longitudinally relatively to the stile members with which they are interfitted, said step means being movable relatively to said one extension member between extended and retracted positions, said step means, in extended position, extending transversely of said one extension member toward said other extension member, and in retracted position, extending longitudinally of and interfitting within said one extension member, and means for guiding the step means from the extended position to the retracted position.

3. An extension step ladder, comprising a pair of laterally spaced stile members comprising longitudinally extending channel members, step members transversely extending between said stile members and secured thereto, and an extension device cooperatively associated with said stile members, said extension device comprising an extension member carried by and longitudinally adjustable relatively to each stile member, said extension member comprising a longitudinally extending channel member interfitting with a companion stile member, step means mounted to move with one and movable in relation to the other of said extension members, said extension members being independently extensible longitudinally relatively to their companion stile members, means for releasably securing said extension members in longitudinally adjusted positions relative to their companion stile members, means for releasably securing said step means in fixed relation with said other extension member, said step means comprising a longitudinally extending channel member movable relatively to said one extension member from an extended position to a retracted position, said step means, in extended position, extending transversely of said one extension member toward said other extension member, and in retracted position, extending longitudinally of and interfitting Within said one extension member, said one extension member with said step means in said interfitted relation being movable longitudinally into telescoped relation with its companion stile member, and means for guiding said step means from the extended position to the retracted position.

4. A ladder, comprising a pair of stile members, means for maintaining said stile members in laterally spaced relation, an extension device comprising an extension member carried by and longitudinally adjustable relatively to each stile member, a step part pivotally mounted on said extension member and movable from a position extending transversely of said extension member toward the opposite extension member and into alignment with another step part to a position extending longitudinally or and interfitting with said extension member, and means for releasably interconnecting said step parts in longitudinally aligned and extended positions to define a step extending transversely between and in rigid relation with said extension members;

5. A ladder, comprising a pair of stile members, means for maintaining said stile members in laterally spaced relation, an' extension device comprising an extension member carried by and longitudinally adjustable relatively to each stile member, a step part pivotally mounted on said extension member and movable from a position extending transversely of said extension member toward the opposite extension member and into alignment with another step part to a position extending longitudinally of and interfitting with said extension member, and means for releasably interconnecting said step parts in longitudinally aligned and extended positions to define a step extending transversely between and in rigid relation with said extension members, said stile members, said extension member and said step part being constituted by channel members, said extension member and said step part-in their retracted positions being retractible inwardly of interfitting with the companion stile member.

' 6, A ladder, comprising a pair of stile members, means for maintaining said stile members in laterally spaced relation, an extension device comprising an extension member carried by and longitudinally adjustable relatively to each stile member, a step part pivotally mounted on said extension member and movable from a position extending transversely of said extension member toward the opposite extension member and into alignment with another step part to a position extending longitudinally of and intertitting with said extension member, and means for releasably interconnecting said step parts in longitudinally aligned and extended positions to define a step extending transversely between and in rigid relation with said extension members, said last mentioned means comprising a member movable from between extended and retracted positions, said member, in extended position,

bridging the adjacent free ends of said step parts for interconnecting the latter, said member, in retracted position, being disposed inwardly of one of said step parts and out of bridging relation with the other step part.

7. A ladder, comprising a pair of stile members, means for maintaining said stile members in laterally spaced relation, anextension device comprising an extension member carried by and longitudinally adjustable relatively to each stile member, a step part pivotally mounted on said extension member and movable from a position extending transversely of said extension member toward the op posite extension member and into alignment with another step part to a position extending longitudinally of and interfitting with said extension member, and means for releasably interconnecting said step parts in longitudinally aligned and extended positions to define a step extending transversely between and in rigid relation with said extension members, said last mentioned means comprising a member movable from an extended position in which said member bridges the adjacent free ends of said step parts for interconnecting the latter to a retracted position in which said member is retracted inwardly of one of said step parts and out of bridging relation with the other step part, said extension member, said step part and said bridging member comprising channel members, said step part and said bridging member, when in retracted position, interfitting with said extension member, and in such interfitted positionbeing retractible inwardly of the companion stile member.

8. A ladder, comprising a pair of stile members comprising longitudinally extending channel members, means transversely extending between and secured to said stile members to retain them in laterally spaced relation, an extension device cooperatively associated with said stile members, said extension device comprising an extension member carried by and longitudinally adjustable relatively to each stile member, said extension member comprising a longitudinally extending channel member interfitting with a companion stile member, a plurality of step parts spaced along and pivotally mounted on said channel member, said step parts being of a longitudinal extent substantially less than the distance between said extension members, each of said step parts being movable from an extended position in which said step part extends transversely between said extension members to a retracted position in which said step part extends longitudinally of and interfits with said extension member, each extension member being independently adjustable longitudinally relatively to its companion stile member to bring a pair of step parts in extended positions on opposite extension members into alignment, and means for releasably interconnecting the adjacent free ends of said longitudinally aligned step parts to produce from aligned step parts a rigid step extending transversely between said extension members,

9. A ladder, comprising a pair of stile members comprising longitudinally extending channel members, means transversely extending between and secured to said stile members to retain them in laterally spaced relation, an extension device cooperatively associated with said stile members, said extension device comprising anextension member carried by and longitudinally adjustable relatively to each stile member, said extension member comprising a longitudinally extending channel member interfitting with a companion stile member, a plurality of step parts spaced along and pivotally mounted on said channel member, said step parts being of a longitudinal extent substantially less than the distance between said extension members, each of said step parts being movable from an extended position in which said step part extends transversely between said extension members to a retracted position in which said step part extends longitudinally of and interfits with said extension member, each extension member being independently adjustable longitudinally relatively to its companion stile member to bring a pair of step parts in extended positions on opposite extension members into alignment, means for releasably interconnecting the adjacent free ends of said longitudinally alinged step parts to produce from aligned step parts a rigid step extending transversely between said extension members, said last mentioned means comprising a member movable between extended and retracted positions, said member, in extended position, bridging the adjacent free ends of said step parts for interconnecting the latter, said member, in the retracted position, being disposed inwardly of one of said step parts and out of bridging relation with the other step part, and means for relasably latching said extension members in a plurality of spaced longitudinally adjusted positions relative to their companion stile members.

10. A ladder, comprising a pair of stile members comprising longitudinally extending channel members, means transversely extending between and secured to said stile members to retain them in laterally spaced relation, and an extension device cooperatively associated with said stile members, said extension device comprising an extension member carried by and longitudinally adjustable relatively to each stile member, said extension member comprising a longitudinally extending channel member interfitting with a companion stile member, a plurality oi step parts spaced along and pivotally mounted on said channel member, said step parts being of a longitudinal extent substantially less than the distance between said extension members, each of said step parts being movable from an extended position in which said step part extends transversely between said extension members to a retracted position in which said step part extends longitudinally of and interfits with said extension member, each extension member being independently adjustable longitudinally relatively to its companion stile member to bring a pair of step parts in extended positions on opposite extension members into alignment, means for releasably interconnecting the adjacent free ends of said longitudinally aligned step parts to produce from aligned step parts a rigid step extending transversely between said extension members, said last mentioned means comprising a member movable between extended and retracted positions, said member, in extended position, bridging the adjacent free ends of said step parts for interconnecting the latter, said member, in the retracted position, being disposed inwardly of one of saidstep parts and out of bridging relation with the other step part, said step parts and said bridging member comprising channel members interfitting with their companion extension member in the retracted positions thereof, said extension members being constructed to be retractible inwardly of their respective companion stile members.

11. A ladder, comprising a pair of stile members, means for maintaining said stile members in laterally spaced relation, anextension device comprising a pair of extension members, and each extension member being carried by and longitudinally adjustable relatively to a respective stile member, a step pivotally mounted on one extension member and movable from a position extending transversely of said one extension member to the region i0 of the other extension member to a retracted position in which said step extends longitudinally of and interfits within said extension member, and means for releasably securing the free end of said step in the extend position thereof to said opposite extension member.

12. A ladder, comprising a pair of stile members,- means -for maintaining said stile members in laterally spaced relation, an extension device comprising a pair of extension members, each extension member being carried by and longitudinally adjustable relatively to a respective stile member, a step pivotally mounted on one extension member and movable from a position extending transversely of said one extension member to the region of the other extension member to a retracted position in which said step extends longitudinally of said extension member and interfits therewith, and means for releasably securing the free end of said step in the extended position thereof to said opposite extension member, said stile members, said extension members and said step comprising channel members, said extension member and said step, when in retracted position, being retractible inwardly of and interfitting with the companion stile member.

13. A ladder, comprising a pair of stile members comprising longitudinally extending channel members, means transversely extending between and secured to said stile members to retain them in laterally spaced relation, an extension device cooperatively associated with said stile members, said extension device comprising a pair of extension members, each=extension member being carried by and longitudinally adjustable relatively to a respective stile member, each extension member comprising a longitudinally extending channel member interfitting with the companion stile member, a step pivotally mounted on the channel member of an extension member with the steps of opposite extension members spaced from each other along the members, said steps being of a longitudinal extent substantially corresponding to the distance between said extension members, each step being movable from an extended position in which said step extends transversely between said extension members to a retracted position in which said step extends longitudinally of and intenfits with its companion extension member, said extension members being independently adjustable longitudinally relatively to their companion stile members, and means for releasably securing the free end of each step in the extended position thereof to an opposite extension member.

14. A ladder, comprising a pair of stile members comprising longitudinally extending channel members, means transversely extending between and secured to said stile members to retain them in laterally spaced relation, an extension device cooperatively associated with said stile members, said extension device comprising a pair of extension members, each extension member being carried by and longitudinally adjustable relatively to a respective stile member, each extension member comprising a longitudinally extending channel member interfitting with the companion stile member, a step pivotally mounted on the channel member of an extension member with the steps of opposite extension members spaced from each other along the members, said steps being of a longitudinal extent substantially corresponding to the distance between said extension members, each step being movable from an extended position in which said step extends transversely between said extension members to a retracted position in which said step extends longitudinally of and interfi-ts with its companion extension member, said extension members being independently adjustable longitudinally relatively to their companion stile members, and means for releasably securing the free end of each step in the extended position thereof to an opposite extension member, said step comprising a channel member, said step channel member, when said step is in retracted position, interfitting with its companion extension member,

11 and said extension members being retractible inwardly of their companion stile members.

15. An extension step ladder, comprising a pair of laterally spaced stile members comprising longitudinally extending channel members, step members transversely extending between said stile members and secured there to, an extension device cooperatively associated with said stile members, said extension device comprising a pair of extension members, each member being carried by and longitudinally adjustable relatively to one of said stile members, each extension member comprising a longitudinally extending channel member having a wall interfitting with its companion stile member, step means mounted on the wall of the channel member of and movable With one extension member and being movable with relation to the wall of the channel member of the other of said extension members, said extension members being independently extensible longitudinally relatively to their companion stile members, means for releasably securing said extension members in longitudinally adjusted positions relative to their companion stile members, means for releasably securing said step means in fixed relation to said other extension member, the means for releasably securing the step means in fixed relation to the other extension member comprising step means carried by said other extension member and capable of being aligned with the first defined step means, and means for releasably retaining the step means in aligned position to define a single step extending transversely between said extension members. a

16. A ladder structure, as defined in claim 15, wherein said step means is constituted by channel members, and said extension member and said step means are retracti'ble inwardly of and in'terfit with the companion stile members.

17. A ladder structure, as defined in claim 15, wherein said releasably retaining means comprise a member for bridging between and interconnecting the step means when aligned.

18. A ladder structure, as defined in claim 15, wherein said step means is constituted by channel members, and said extension member and said step means are retractible inwardly of and interfit with the companion stile members, and said releasably retaining means comprise a member for bridging between and interconnecting the step means when aligned, and said bridging member is of channel construction and interfits into the channel member of one of the step-means.

References Cited in the file of this patent UNITED STATES PATENTS 359,716 Di'lts Mar. 22, 1887 409,711 Sioldes Aug. 27, 1889 623,540 Hall Apr. 25, 1899 722,409 Paskell Mar. 10, 1903 1,169,700 WaltoWer Jan. 25, 1916 1,371,125 Speck'man Mar. 8, 1921 1,513,854 Pettiford Nov. 4, 1924 1,579,574 Taylor Apr. 6, 1926 1,731,611 Clark Oct. 15, 1929 2,588,959 Campbell Mar. 11, 1952 

